Integrated cryogenic receiver front-end

ABSTRACT

A cryogenic receiver front-end includes a heat sink having a mounting surface and a plurality of fins, a cryocooler mounted to the mounting surface of the heat sink, a heat rejector surrounding the cryocooler, the heat rejector including a plurality of pliable c-shaped recesses therein, and a plurality of heat pipes. Each heat pipe has first and second ends, the first ends of the plurality of heat pipes are disposed in respective c-shaped recesses of the heat rejector. A working fluid is contained inside the heat pipes. The second ends of the plurality of heat pipes are thermally coupled to the heat sink. A weather resistant enclosure unit is mounted to the heat sink and encloses the components of the cryogenic receiver front-end.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

The U.S. Government may have a paid-up license in this invention and aright in limited circumstances to require the patent owner to licenseothers on reasonable terms as provided for by the terms of Contract No.DMEA90-03-C-0302 awarded by the Defense MicroElectronics Activity (DMEA)established by the Department of Defense.

FIELD OF THE INVENTION

The field of the invention generally relates to high temperaturesuperconducting (HTS) front-end filter systems for use in, for example,wireless applications. The present invention has particular usefulnessfor wireless PCS carriers but is generally applicable to all wirelessfront-end applications requiring high sensitivity and high selectivity.

BACKGROUND OF THE INVENTION

It is known that cryogenically cooled front-end receivers can be used toprovide increased sensitivity and selectivity for expanding coverage andreducing interference in noise-limited and interference-limited cellsites. In the context of wireless voice services, cryogenically cooledfront-ends provide significant enhancements in network performanceincluding, for example, greater call capacity, fewer coverage gaps bothoutside and inside buildings, as well as an overall improvement in voicequality.

Cryogenically cooled front-ends include one or more HTS radio frequencyRF filters that, because of their near-zero resistance, provide highselectivity with low loss. In order for the HTS filters to functionproperly, however, the HTS filters must be cooled to cryogenictemperatures. In order to cool the filters in the front-end, acryocooler such as a Stirling cycle cryocooler is used to maintain thefilters (as well as other associated electronics) at cryogenictemperatures.

Because of the cryogenic temperatures needed to function properly,cryogenic front-ends must deal with a whole host of thermal managementissues. For example, for a cryocooler to function properly, the heat ofcompression must be efficiently and reliably rejected to the ambientenvironment. If the heat generated in the compression cycle of thecryocooler cannot be readily rejected, it will result in inefficientcryocooler operation and even crycooler shut down or failure. Stillother components of the front-end device can radiate heat that needs tobe transferred to ambient.

Various methods and devices have been employed to produce cryogenicallycooled front-ends. U.S. Pat. No. 6,263,215 discloses acryoelectronically cooled receiver front-end for mobile radio systems.The receiver front-end consists of a mast mounted portion of thereceiver front-end, a compressor located off the mast, and a conduit fordelivering cooling fluid from the compressor to the mast-mountedreceiver front-end. This system suffers from the limitation that largeamounts of energy are wasted by having to pump cooling fluid from thecompressor to the mast-mounted receiver front-end (which may be as highas 200 feet above the ground.)

U.S. Pat. No. 6,112,526 discloses a HTSC filter system that contains acryocooler and dewar assembly, a heat dissipation assembly, and at leastone heat pipe providing thermal coupling between the heat dissipationassembly and the cryocooler and dewar assembly. In certain embodimentsof the system of the '526 patent, one or more fan units may be needed toprovide forced air over the heat dissipation assembly.

It is also known to mount cryogenically cooled front-ends in a structuresuch as a shed at the bottom of a wireless base station. In this system,the cryogenically cooled front-end is mounted in a rack or cable traymount. In both options, however, forced convection cooling using a fanunit is required to ensure proper thermal management.

There thus is a need for a integrated cryogenic receiver front-end thatcan be located in or adjacent to a wireless base station that does notrequire a fan unit (either internal or external). There is a furtherneed for a weatherized integrated cryogenic receiver front-end that canbe mounted adjacent to a base station in an outdoor environment. Thereis a further need for an integrated cryogenic receiver front-end thatcan more efficiently transfer heat generated by power amplifiers,multiplexers, and electronics to ambient.

SUMMARY OF THE INVENTION

In a first aspect of the invention, a cryogenic receiver front-endincludes a heat sink, the heat sink having a mounting surface and aplurality of fins. A cryocooler is mounted to the mounting surface ofthe heat sink. A heat rejector surrounds the cryocooler and includes aplurality of c-shaped recesses therein. The cryogenic receiver front-endfurther includes a plurality of heat pipes having a working fluiddisposed therein, each heat pipe having first and second ends, the firstends of the plurality of heat pipes disposed in respective c-shapedrecesses of the heat rejector, the second ends of the plurality of heatpipes being thermally coupled to the heat sink. An enclosure unit ismounted to the heat sink.

In a second separate aspect of the invention, a method of dissipatingheat from a heat generating component in or adjacent to a base stationincludes the steps of providing a heat sink, the heat sink being locatedin or adjacent to a base station. At least one heat generating componentis provided. A heat pipe is provided for the at least one heatgenerating component, the heat pipe having a first end and a second endand a working fluid contained therein, the first end of the heat pipebeing thermally coupled to the at least one heat generating component,the second end of the heat pipe being thermally coupled to the heatsink.

In a third aspect of the invention, a thermally conductive interfacebetween a heat source and a heat sink is provided and includes a heatrejector being thermally coupled with a heat source, the heat rejectorincluding a c-shaped recess therein for receiving one end of a heat pipehaving a working fluid therein, the heat sink being thermally coupled toan opposing end of the heat pipe.

It is an object of the invention to provide a cryogenic receiverfront-end that can be located in or adjacent to a base station that doesnot require the use of an external fan or similar device to aid inexpelling heat to ambient. The cryogenic receiver front-end has a smallsize and can be mounted either indoors or outdoors. The cryogenicreceiver front-end is weather resistant (NEMA-4X compliant) and can bemounted, for example, on a pad, wall, shelf, or pole.

It is a further object of the invention to provide a thermallyconductive interface between a heat source and a heat sink that uses aheat pipe mounted to a novel heat rejector.

It is yet another object of the invention to provide a method ofdissipating heat from heat generating components located in or adjacentto a wireless base station.

These and further objects of the invention are described in more detailbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an end view of the cryogenic receiver front-endaccording to one embodiment of the invention.

FIG. 2 is an isometric view of the integrated cryogenic receiverfront-end of FIG. 1.

FIG. 3(a) illustrates a wireless base station having the cryogenicreceiver front-end installed inside a structure.

FIG. 3(b) illustrates the cryogenic receiver front-end mounted to a pad.

FIG. 3(c) illustrates the cryogenic receiver front-end mounted to awall.

FIG. 3(c) illustrates the cryogenic receiver front-end mounted to apole.

FIG. 4(a) illustrates the architecture of the cryogenic receiverfront-end for the dual duplexed RF path.

FIG. 4(b) illustrates the architecture of the cryogenic receiverfront-end for the simplexed RF path.

FIG. 5(a) illustrates an end view of the cryogenic receiver front-end.

FIG. 5(b) is a sectional view of the cryogenic receiver front-end takenalong the A-A line of FIG. 5(a).

FIG. 6(a) is an isometric view of the thermal management system used inthe cryogenic receiver front-end.

FIG. 6(b) is an end view of the thermal management system shown in FIG.6(a).

FIG. 7 is a detail view of the heat sink, heat pipe, and heat pipecover.

FIG. 8(a) illustrates the heat rejector without a heat pipe.

FIG. 8(b) illustrates the heat rejector of FIG. 8(a) having a heat pipedisposed within the c-shaped recess of the heat rejector. The heatrejector is not clamped around the heat pipe.

FIG. 8(c) illustrates the heat rejector of FIG. 8(a) having a heat pipedisposed within the c-shaped recess of the heat rejector. The heatrejector is clamped around the heat pipe.

FIG. 9 illustrates a single heat pipe according to one preferred aspectof the invention.

FIG. 10 schematically illustrates a thermally conductive interfacebetween a heat source and a heat sink that uses a heat rejector and aheat pipe.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate a cryogenic receiver front-end 2. The cryogenicreceiver front-end 2 includes an enclosure 4 that surrounds and protectsthe components inside the cryogenic receiver front-end 2. The enclosure4 is designed to satisfy the NEMA (National Electrical ManufacturersAssociation) 4X standard. Accordingly, the enclosure 4 is constructed toallow either indoor or outdoor use. The enclosure 4 has a size ofapproximately 24″W×24″D×24″H.

For outdoor use, the enclosure provides a reasonable degree ofprotection against falling dirt, rain, sleet, snow, windblown dust,splashing water, hose-directed water, and ice. The enclosure 4 ispreferably made from a corrosion resistant metal.

With reference now to FIGS. 1, 2, and 3(a), the cryogenic receiverfront-end 2 is used in connection with a wireless base station 6 thatboth receives and transmits wireless data (e.g., voice signals or otherdata) as part of a wireless network. The cryogenic receiver front-end 2may be mounted on a pad 8 (FIG. 3(b), on a shelf 9 (FIG. 3(a)) or wall10 (FIG. 3(c), or on a pole 12 (FIG. 3(d)). With respect to mounting thereceiver front-end 2 on a pole 12, the pole 12 might include one of themembers of the antenna tower located near ground level. The cryogenicreceiver front-end 2 is preferably located in or adjacent to a wirelessbase station 6. With respect to locating the cryogenic receiverfront-end 2 in a base station 6, the device is located within somestructure 14 which may include a building, shed, or the like. Thecryogenic receiver front-end 2 can also be located in an outsideenvironment exposed to ambient (i.e., shown in FIGS. 3(b), 3(c), and3(d)).

Referring to FIGS. 1, 2, and 3(a) the cryogenic receiver front-end 2preferably has one or more weatherized connectors (such as 7-16 DIN typefemale) that connect to the antenna 18 of a base station 6 via cable 17(only four are shown in FIGS. 1 and 2 and the connectors 16 arecontained in cable boots). The one or more connectors 16 are divided upinto three sectors (α, β, γ) for each of the three sectors of the basestation 6. The cryogenic receiver front-end 2 also includes one or moreweatherized connectors 20 (such as 7-16 DIN type female) that connect tothe base station 6 or power amplifier (not shown). Only four connectors20 are shown in FIGS. 1 and 2 (the connectors 20 are contained in cableboots).

The cryogenic receiver front-end 2 includes both a dual duplexed RF pathshown in FIG. 4(a) as well as a simplexed RF path shown FIG. 4 (b). Asource of either AC or DC voltage (110/220 VAC or 24/48 VDC) is used topower the cryogenic receiver front-end 2. The cryogenic receiverfront-end 2 includes one or more HTS filters 22 disposed in acryogenically cooled environment. HTS filters 22 and associatedfront-end electronics are known to increase capacity utilization, reducethe number of blocked calls, extend coverage of an existing base station6, as well as enable higher data transmission rates. In order tomaintain the HTS components at cryogenic temperatures, a cryocooler 24(shown in FIGS. 5(b), 6(a), and 6(b)) is used to cool the HTS filters22. The use of a cryocooler 24 poses significant thermal managementissues. In order to produce a usable front-end HTS receiver 2, the heatgenerated from the cryocooler 24 as well as the heat generated in theother components of the HTS front-end device (i.e., heat generated fromelectrical or RF energy) must be efficiently transferred to the ambientenvironment.

In accordance with the invention, the cryogenic receiver front-end 2uses a unique heat rejection system that is able to passively rejectheat to the outside environment without the aid of a fan or othersimilar device that would enhance convection on or around the device.Preferably, the cryogenic receiver front-end 2 is able to maintain atemperature difference of less than about 20° C. between the temperatureof the heat rejector of the cryocooler 22 and the ambient temperature.

FIG. 5(b) shows an interior view of the cryogenic receiver front-end 2taken along the line A-A of FIG. 5(a). A multiplexer 23 (which may be aduplexer, or a dual duplexer) is preferably disposed within theenclosure 4 and opposite the heat sink 26. It is possible, however, tolocate the multiplexer 23 on the heat sink 26. As seen in FIG. 5(b), acryocooler 24 is disposed on a heat sink 26 using a carriage assembly28. The cyrocooler 24 includes a dewar 30 that contains the HTS filters22. A heat rejector 32 surrounds the cryocooler 24 and is used totransfer the heat of compression generated by the cryocooler 24 toambient as described in more detail below. The cryocooler 24 ispreferably a linear cryocooler 24 such as a Stirling cryocooler 24. Theinvention, however, is not limited to a particular type of cryocooler24.

As seen in FIG. 5(b), the heat sink 26 and fins 36 are orientedvertically within the enclosure 4. The vertical orientation is used tocreate a chimney effect with hot air rising between adjacent fins 36 tothe outside environment.

FIGS. 6(a) and 6(b) show a detailed view of the cryocooler 24 and theheat rejection system used to transfer heat to ambient. The heatrejection system includes a heat sink 26 having a mounting surface 34and plurality of fins 36. The cryocooler 24 is mounted to the mountingsurface 34 of the heat sink 26 by the carriage assembly 28. Preferably,the heat sink 26 is made from a thermally conductive material such asaluminum. One preferred material for the heat sink 26 and fins 36 isaluminum alloy 6063. The fins 36 are preferably swaged to optimize heattransfer for natural heat convection.

Additional electronic components of the cryogenic receiver front-end 2are also directly mounted to the mounting surface 34 of the heat sink26. These components include the power supply 38, power converter 40,diode 42 (for power system protection), DSP board 44, and one or more RFcomponents such as amplifiers 46 (six amplifiers in total are shown).The additional RF components may comprise additional amplification, suchas second stage amplification, mixing devices for frequency conversionand/or IF signal processing and analogue to digital converter (A to Dconverter). The electronic components are advantageously mounteddirectly to the heat sink 26 in order to more efficiently transfer heatgenerated thereby to ambient. Heat generated by the various electroniccomponents is transferred to the plate portion of the heat sink 26 andthen to the fins 36.

FIG. 6(b) shows an end view of the dewar 30 of the cryocooler 24.Electrical connectors 44 (12 in total—6 input and 6 output) permitelectrical communication with the six HTS filters 22 contained withinthe dewar 30. A dewar harness 47 gives electrical access to the insideof the dewar 30 for a cold bypass for each of the six HTS filters 22contained within the dewar, temperature sensors for monitoring thetemperature of the dewar 30/HTS filters 22, ground, and LNAs. Anexternal (non-cryogenically cooled) bypass might also be used.

A thermally conductive interface is provided between the heat rejector32 of the cryocooler 24 and the heat sink 26. In the preferredembodiment, a plurality of heat pipes 48 are used to efficientlytransfer heat from the heat rejector 32 to the heat sink 26. As seen inFIG. 6(a), two separate heat pipes 48 are used to transfer heat to theheat sink 26. The heat pipes 48 are thermally coupled to the heatrejector 32 using a pliable c-shaped recess (shown in detail in FIGS.8(a), 8(b), and 8(c)) for receiving ends of the heat pipes 48. The heatpipes 48 are bent into an elbow shape such that opposing ends of theheat pipes 48 can make thermal contact with the heat sink 26.

Referring to FIG. 6(a), opposing ends of heat pipes 48 are thermallycoupled to the heat sink 26 by using a pair of heat pipe covers 50. Theheat pipe covers 50 pinch the heat pipes 48 between the heat sink 26 andthe underside of the heat pipe covers 50. Bolts and associated nuts 52are used to secure the heat pipe covers 50 to the heat sink 26.Preferably, the heat pipe covers 50 are formed from oxygen free highconduction (OFHC) copper.

FIG. 7 shows an end view of the mating arrangement between the heat pipecover 50 and the heat sink 26. As seen in FIG. 7, a hemispherical groove52 is formed in the heat sink 26. Similarly, another hemisphericalgroove 54 is formed in the underside of the heat pipe cover 50. Athermally conductive compound 56 is applied at the interface between theheat sink 26 and heat pipe cover 50 to improve the thermal transferefficiency between the two components. Preferably, a thermallyconductive compound such as THERMAGON T-PCM 910 (a non-reinforced boronnitride filled film) is used.

FIGS. 8(a)illustrates one side of the heat rejector 32 used to transferheat from the cryocooler 24. The heat rejector 32 is formed from athermally conductive metal such as, for example, copper. Preferably, thethermally conductive metal is annealed OFHC copper. In a preferredmethod of forming the heat rejector 32 half hard or full hard OFHCcopper is annealed (softened) by brazing the copper to at least 450° C.The annealed copper that results is particularly pliable and can form anexcellent thermal contact with the heat pipes 48.

The heat rejector 32 includes a c-shaped recess 58 that receives an endof the heat pipe 48. The heat rejector 32 also includes a plurality ofholes 60 that can accept bolts 62 (FIG. 8(b)) used to clamp the c-shapedrecess 58 around the heat pipe 48.

Referring now to FIG. 8(b), one end of the heat pipe 48 is inserted intothe c-shaped recess 58. As seen in the end view of FIG. 8(b), in thenon-clamped position, there is a small gap between the outer surface ofthe heat pipe 48 and the inner surface of the c-shaped recess 58. Thec-shaped recess 58 is then clamped around the outer surface of the heatpipe 48 by inserting the bolts 62 into the corresponding holes 60 in theheat rejector 32 and tightening nuts 64. An alternative to using bolts62 and nuts 64 would be to use screws in threaded holes within the heatrejector 32. It is preferable, however, to use bolts 62 and nuts 64 toprevent the possibility of stripping the threads in the heat rejector 32during tightening.

FIG. 8(c) illustrates the c-shaped recess 58 in the clamped state. Inthe clamped state, there is no gap between the outer surface of the heatpipe 48 and the inner surface of the c-shaped recess 58 as the recesshas fully conformed to the outer surface of the heat pipe 48. It shouldbe understood that the pliable nature of the c-shaped recess 58 allowsexcellent thermal contact between the heat pipe 48 and the heat rejector32 even if there are small variations or imperfections in the exteriorsurface of the heat pipe 48.

FIG. 9 illustrates a heat pipe 48 according to a preferred aspect of theinvention. The heat pipe 48 is preferably formed from 0.5″ OFHC copper.As seen in FIG. 9, the heat pipe 48 is bent into an elbow shape. For theembodiment with the cryogenic receiver front-end 2, the heat pipe 48 ispreferably bent to an angle greater than 90° to utilize gravity duringthe liquidation portion of the heat pipe 48 cycle. A plug 66 is formedin the end of the heat pipe 48 that is secured to the heat rejector 32.The plug is formed from a material that is non-reactive with the workingfluid 70. The plug 66 fits within the internal diameter of the heat pipe48 so as not to interfere with the close fit formed between the heatpipe 48 and the heat rejector 32.

Also located inside the evaporator section of the heat pipe 48 (thesection of heat pipe 48 secured within the heat rejector 32) is a wiremesh or screen 68. The evaporator section is retained in the c-shapedrecess 58 when the heat pipe 48 is secured to the heat rejector 32. Aworking fluid 70 is located inside the heat pipe 48 and is used totransfer heat from the evaporator portion to the cooler condenserportion secured to the heat sink 26. In a preferred aspect of theinvention, the working fluid 70 is methanol. However, other workingfluids such as ammonia, water, nitrogen, neon, and ethane can be used. Apinch 72 (see also FIGS. 8(b) and 8(c)) is formed at the end of the heatpipe 48 opposite the end having the plug 66. The pinch 72 is formedafter filing the heat pipe 48 with the working fluid 70. An epoxy (notshown) is preferably placed over the pinch 72 to protect the pinchedzone from damage that might cause working fluid 70 to leak out.

The use of one or more heat pipes 48 in the cryogenic receiver front-end2 provides a thermal management system that is able to passively rejectheat to ambient without the aid of a fan. Moreover, the heat pipes 48are fully contained within the enclosure 4 (i.e., the heat pipes 48 donot pass through the walls of the enclosure 4) and therefore do notjeopardize the environmental protection quality of the cryogenicreceiver front-end 2.

While the preferred embodiment of the invention uses a plurality of heatpipes 48 to transfer the heat of compression generated from a cryocooler24, it should be understood that the heat rejector 32 and heat pipe(s)48 may be used to dissipate heat from any number of heat generatingcomponents that are in a cryogenic receiver front-end 2 located in oradjacent to a base station 6. In addition, it may be the case that asingle heat pipe 48 provides sufficient heat transfer from a heatgenerating component to a heat sink.

FIG. 10 broadly illustrates an embodiment of a thermally conductiveinterface 80 used to transfer heat from a heat source 82 to a heat sink84. The heat source 82 may include, for example, amplifier(s),multiplexer(s), duplexers(s), a power supply, a power converter, andcontrol circuitry. In the broadest sense of the invention, the heatsource 82 may include any device that generates heat either fromelectrical energy or RF energy.

The heat source 82 is preferably thermally coupled to a heat rejector 86having at least one c-shaped recess 88 of the type described in detailabove. A heat pipe 90 (or multiple heat pipes 90 if more than onec-shaped recess 88 is present) is disposed inside the c-shaped recess 88in a clamped arrangement thereby thermally coupling the heat pipe 90 tothe heat rejector 86. The heat pipe 90 is thermally coupled at the otherend to the heat sink 84. The heat pipe 90 may be thermally coupled tothe heat sink 84 using heat pipe covers 50 as described above (not shownin FIG. 10) or any other arrangement that forms good thermal contactbetween the heat pipe 90 and the heat sink 84.

The heat pipe 90 may include a plug 92 at one end and a pinch 94 at theother end to retain a working fluid therein (not shown). In FIG. 10, theheat pipe 90 is shown having an elbow shape although other geometries(even straight) can be employed. It should be understood that theinvention is not limited to the specific construction of the heat pipe90 described above as other heat pipe 90 constructions are alsocontemplated to fall within scope of the invention.

While the invention is susceptible to various modifications, andalternative forms, specific examples thereof have been shown in thedrawings and are herein described in detail. It should be understood,however, that the invention is not to be limited to the particular formsor methods disclosed, but to the contrary, the invention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the appended claims.

1. A cryogenic receiver front-end comprising a heat sink, the heat sinkcomprising a mounting surface and a plurality of fins; a cryocoolermounted to the mounting surface of the heat sink; a heat rejectorsurrounding the cryocooler, the heat rejector including a plurality ofc-shaped recesses therein; a plurality of heat pipes, each heat pipehaving first and second ends, the first ends of the plurality of heatpipes disposed in respective c-shaped recesses of the heat rejector, thesecond ends of the plurality of heat pipes being thermally coupled tothe heat sink, the plurality of heat pipes having a working fluiddisposed therein; and an enclosure unit mounted to the heat sink.
 2. Thethermally conductive interface of claim 1, wherein the heat rejector ismade of a metal.
 3. The cryogenic receiver front-end of claim 2, theheat rejector being formed from annealed copper.
 4. The cryogenicreceiver front-end of claim 1, the plurality of heat pipes being formedfrom OFHC copper.
 5. The cryogenic receiver front-end of claim 1,wherein the enclosure unit satisfies the NEMA-4X standard.
 6. Thecryogenic receiver front-end of claim 1, wherein the cryogenic receiverfront-end is disposed inside a structure.
 7. The cryogenic receiverfront-end of claim 1, wherein the cryogenic receiver front-end isdisposed in an outside environment.
 8. The cryogenic receiver front-endof claim 1, wherein the cryogenic receiver front-end is disposed in oradjacent to a base station.
 9. The cryogenic receiver front-end of claim1, wherein the cryogenic receiver front-end is mounted to a pad.
 10. Thecryogenic receiver front-end of claim 1, wherein the cryogenic receiverfront-end is mounted to a wall.
 11. The cryogenic receiver front-end ofclaim 1, wherein the cryogenic receiver front-end is mounted to a pole.12. The cryogenic receiver front-end of claim 1, wherein the workingfluid is selected from the group consisting of methanol, ammonia, water,nitrogen, neon, and ethane.
 13. A method of dissipating heat from a heatgenerating component located in or adjacent to a base station, themethod comprising the steps of: providing a heat sink, the heat sinkbeing located in or adjacent to a base station; providing at least oneheat generating component; providing a heat pipe for the at least oneheat generating component, the heat pipe having a first and a second endand a working fluid contained therein, the first end of the heat pipebeing thermally coupled to the at least one heat generating component,the second end of the heat pipe being thermally coupled to the heatsink.
 14. The method of claim 13, wherein the heat sink comprises aplate having a plurality of fins located thereon.
 15. The method ofclaim 13, wherein the heat generating component is selected from thegroup consisting of amplifier, multiplexer, power supply, powerconverter, and control circuitry.
 16. The method of claim 13, whereinthe heat pipe is thermally coupled to the at least one heat generatingcomponent using a heat rejector including a c-shaped recesses therein,the first end of the heat pipe being disposed within the c-shapedrecess.
 17. The method claim 13, wherein the working fluid is selectedfrom the group consisting of methanol, ammonia, water, nitrogen, neon,and ethane.
 18. The method of claim 13, wherein the heat pipe is fullyenclosed within an enclosure surrounding the at least one heatgenerating component.
 19. A thermally conductive interface between aheat source and a heat sink comprising: a heat rejector being thermallycoupled with a heat source, the heat rejector including a c-shapedrecess therein for receiving one end of a heat pipe having a workingfluid therein, the heat sink being thermally coupled to an opposing endof the heat pipe.
 20. The thermally conductive interface of claim 19,wherein the heat rejector is made of a metal.
 21. The thermallyconductive interface of claim 20, wherein the heat rejector is made ofannealed copper.
 22. The thermally conductive interface of claim 19,wherein the heat source is a cryocooler.
 23. The thermally conductiveinterface of claim 19, wherein the heat source is selected from thegroup consisting of amplifier, multiplexer, power supply, powerconverter, and control circuitry.
 24. The thermally conductive interfaceof claim 19, further comprising means for clamping the c-shaped recess.